Clamshell bucket closure attachment



Oct 1, 9 0. c. STINE 2,808,166

CLAMSHELL BUCKET CLOSURE ATTACHMENT Filed Feb. 28; 1955 5 Sheets-Sheet 1 OLIVER C. STINE,

IN V EN TOR HUEBNER, BEEHLER, v WORREL a HERZIG,

ATTORNEYS.

o. c. STlNE 2,808,166

CLAMSHELL BUCKET CLOSURE ATTACHMENT 5 Sheets-Sheet 2 Oct. 1, 1957 Filed Feb. 28, 1955 INVENTOR BEEHLER,

OLIVER c. STINE,

H UEBNER, WORREL 8 HERZIG,

' ATTORNEYS.

I H W" I a a I M m! :0:

Oct. 1, 1957 o. c. STINE CLAMSHELL BUCKET CLOSURE ATTACHMENT 3 Sheets-Sheet 3 Filed Feb. 28, 1955 -Illl Ill IIIIIIIIIIIII e OLIVER c. STINE,

INVENTOR H UEBNER, BEEHLER,

WORREL f9 HERZIG,

, ATTORNEYS.

United States Patent CLAMSHELL BUCKET CLOSURE ATTACHMENT Oliver C. Stine, Northridge, Calif.

Application February 28, 1955, Serial No. 490,753

8 Claims. (Cl. 214-656) The present invention relates to a rapid takeup and rapid release mechanism for speeding up the closing and opening operations of a clamshell bucket of the type used with a crane for digging and handling earth and gravel, for example.

The clamshell bucket of a crane is supported from the boom by a holding line connected to a drum in the cabin of the crane for raising and lowering the bucket. A closing line also normally is connected to the drum and extended from the boom to a block and tackle, or similar arrangement, in the clamshell bucket. The block and tackle arrangement, through which the closing line passes, multiplies the closing force applied to the clamshell bucket from the drum in the cabin of the crane. However, in the conventional closing line block and tackle arrangement the force multiplication, or mechanical advantage, is accomplished at the expense of distance of travel. That is, the amount of closing line to be reeled in and wound up by the drum is multiplied by a factor about equal to the mechanical advantage produced. This fact causes the loss of considerable time during both the bucket closing and opening operations because the crane mechanism ordinarily does not have the necessary high speeds required for rapidly closing and opening the clamshell bucket.

Accordingly, it is an important object of the invention to provide an etficient mechanism for rapidly closing and opening a clamshell bucket provided with a closing line block and tackle arrangement.

Another object is to provide a pulley arrangement for the closing line wherein the pulleys can be moved apart to speed up the closing or opening operations of a clamshell bucket.

A further object is to provide a convenient mechanism, capable of operation by the operator of a crane, for efficiently overcoming the effect of increased travel distance produced in the closing line during closing of a clamshell bucket provided with a closing line block and tackle arrangement.

Additional objects will become apparent from the following description.

Broadly stated, the invention comprises combining a moveable pulley means, or moveable sheave means with a closing line block and tackle arrangement employed in a clamshell bucket. The moveable pulley means is provided with a mechanism for moving the pulley relative to the closing line engaged by the block and tackle and the pulley. When it is desired to close the clamshell bucket, the moveable pulley is moved relative to the closing line so that the strands of closing line engaged by the pulley are lengthened and only a fraction of the increased length of closing line need be reeled in and wound on the drum.

A more detailed description of a specific embodiment of the invention is given with reference to the drawings,

wherein:

Figure l is an elevational view showing a crane with a clamshell bucket containing a block and tackle, and a 2,808,166 Fatented Oct. 1, 1957 "ice moveable pulley 10 and associated mechanism mounted on the boom of the crane;

Figure 2 is a plan View showing the moveable pulley and associated mechanism for moving the pulley relative to the closing line and the boom of the crane;

Figure 3 is a side View showing the pulley and associated mechanism of Figure 2;

Figure 4 is a fragmentary detail view showing a rack and pinion portion of the mechanism for moving the pulley shown in Figures 2 and 3.

Figure 5 is a cross-sectional elevational view taken on the line 55 of Figure 2;

Figure 6 is a similar view taken on the line 66 of Figure 2;

Figure 7 is a diagrammatic view of the closing line showing its engagement with the pulley and sheaves of the associated mechanism; and

Figure 8 is a perspective view showing another specific embodiment of the invention employing two moveable pulleys, a piston and cylinder mechanism for moving the pulleys relative to each other and showing diagrammatically a crane cabin and hydraulic system.

In the specific embodiment shown in Figures 1 to 7, the moveable pulley or sheave 10 is rotatably mounted in a block 11 fixed to a moveable platform 12. Platform 12 is separated from a plate 13 by rollers 14 mounted on axles 16. The axles 16 are bolts provided with washers 17 011 either side of the rollers 14. The axle-bolts 16 hold the platform 12 and plate 13 together in parallel relationship to form a carriage 15 for movement on a frame 20 formed of tubular sides 18 and 19 and ends 21 and 22 as shown in phantom at 23.

The closing line 24 (Figure 3) from the block and tackle 26 in the clamshell bucket 27 passes over a sheave 28 rotatably mounted on the end of a boom 29 and over the pulley 10. From pulley 10 the under strand of closing line 24 passes around sheave 31 rotatably mounted on the tubular frame end 21. The strand of closing line 24 leaving sheave 31 passes around a lower drum-pulley 32 (Figure 6) fixed to a brake drum and rotatably mounted at an angle to platform 12 in a bearing assembly 34 on an axle 36. Bearing assembly 34 and axle 36 in turn are mounted at an angle to platform 12 and plate 13.

After passing around lower drum-pulley 32, closing line 24 passes around upper drum-pulley 37 (Figure 5) fixed to a brake drum 38 and rotatably mounted parallel with platform 12 in a bearing assembly 39 on an axle 41. Bearing assembly 39 and axle 41 are mounted transversely between platform 12 and plate 13. As best shown in Figure 6, drum-pulleys 32 and 37 are mounted at an angle to each other so that the strand of closing line 24 leaving upper drum pulley 37 can pass by the strand of closing line 24 approaching lower drum pulley 32 Without contacting the same on the lower side thereof. 7

The portion of closing line 24 leaving upper drum pulley 37 passes under a sheave 42 rotatably mounted on the tubular frame end 22 and onto a drum 43 mounted in the cabin 44 of the crane. When the drum 43 is turned by the engine (not shown) of the crane to reel in and wind up the closing line 24, the clamshell bucket 27 is closed, if it happens to be in the open position, by the action of the block and tackle 26. This is accompanied by an upward movement of the lower block of the block and tackle 26 toward the upper block amid the production of a mechanical advantage of multiplied force 'imparted to the jaws of the bucket 27. This multiplied force is necessary for the lips and teeth of the bucket to bite into earth, gravel, or the like, to load the bucket 27;

Movement of the lower block toward the upper block in the block and tackle 26, however, because of the plu tackle 26, requires the relatively rapid reeling in of a relatively long length of closing line 24. The crane'op erator accomplishes this in the mechanism of the invention illustrated in Figures 1 to 7 by drawing closing, line 24 through pulley 10, sheave 31, lower drum-pulley 32, upper drum pulley 37 and sheave 42 while carefully applyingbrakes to the drum-pulleys 32 and 37.

The brakes are applied by regulating the vacuum on a diaphragm valve 46 (Figure 2) by means of a control valve 47 in the cabin 44 of the crane. The rod 48 of the diaphragm. valve 46 is connected to one end each of friction brake shoes 49,51 and 52, provided with brake linings 53, 54 and 56, respectively. The other end of each of the brake shoes is fixed to platform 12 by means of clamps 57, 58 and 59, respectively. Brake shoes 49 and 51 on brake drums 33 and 38, respectively, are provided with compression springs 61 and 62, respectively, which normally urge the brake shoes 49 and 51 into an open, unapplied position, permitting free rotation of drum-pulleys 32 and 37 when rod 48 is urged outward of diaphragm valve 46.

Brake shoe 52 (Figure on the other hand, is provided with a compression spring 63 which normally urges the brake shoe 52 into a closed, applied position, tending to lock the brake drum 55 and pinion gear 64 against rotation. Pinion 64 is keyed to shaft 66, which in turn is-keyed to brake drum 55 so that drum 55, pinion 64 and shaft 66 rotate together as a unit in bearing assemblies 67 and 68. The bearing assemblies 67 and 68 are mounted on the outer surfaces of platform 12 and plate 13 as shown. It will be seen, therefore, that as the operator of the crane applies the brakes to drum-pulleys 32 and 37, he releases the brake on drum 55 so that as the rotation of drum-pulleys 32 and 37 is decelerated or stopped, the rotation of drum 55 is started or accelerated correspondingly. The rotation of drum 55 turns pinion gear 64 and causes gear 64 to move along rack 69 fixed to tubular side 19 of the tubular carriage frame 20. As the drum 43 is pulling on closing line 24, while closing bucket 27, pinion gear 64 is moved from the upper end of rack 69 toward the lower end thereof, and platform 12 and move able pulley on carriage are moved in the same direction, as shown by the arrow in Figure 7.

This movement of moveable pulley 10 away from the upper frame end 21 increases the distance between sheave 31 and pulley 10 and causes a simultaneous lengthening of three separate strands of closing line 24. The three strands are (Figure 7): strand 24a approaching pulley 10, strand 24!) leaving pulley 10 and approaching sheave 31, and strand 24c leaving sheave 31. That is, the movement of pulley 10 over a given distance downward on frame (away from frame end 21) causes the pulling in over sheave 28 of a length of closing line equal to about three times the given distance of movement of pulley 10, and corresponding to the lengthening of the three strands, 24a, 24b and 24c of closing line 24, as mentioned above.

The downward movement of carriage 15 (Figure 7) and pulley 10 in the direction of the arrow is relatively rapid. Closing line 24 is pulled very'rapidly away from the block and tackle 26 in bucket 27. The lower block of block and tackle 26 is quickly elevated and the jaws of bucket 27 are closed both rapidly and forcefully while biting into the rocky earth, gravel, etc.,' to be loaded. This rapid and forceful action results in fully loading the bucketand speeds up digging, handlingand dumping of material.

While hoisting loaded bucket 27, the operator of the crane, by manipulating air pressure, control valve 47, actuates diaphragm valve 46 to urgerod 48 outward of valve 46. Brake shoes 49 and 51 are then released from brake drums 33and 38 and drum pulleys 32 and 37 are free to rotate; Carriage 15 is locked in the lowered positionyon frame 20, shown in phantom. in Figure 2, be cause brake shoe 52 now is applied to brake dnmi 55.

7 p 4 Bucket 27 is hoisted or lowered by the turning of drum 43 to wind or unwind closing line 24 while the holding line 71 also is wound up or unwound, as the case may be. Opening of the bucket 27 also is greatly speeded up, as will be seen from the description and explanation of the closing operation given above. Drum pulleys 32 and 37 are again locked against turning by applying brake shoes 49 and 51, and pinion gear 64 is freed for rotation by releasing brake shoe 52 from brake drum 55. Carriage 15 and pulley 10 are then permitted to move rapidly upward on frame 2t} to their original position shown in Figure 2 by unwinding cable from drum 43. During this movement of the carriage 15 over a given distance, there is very rapidly released to the block and tackle 26 a length of closing line 24 equal to the sum of the lengths of strands 24a, 24b and 240 of the closing line, which is approximately equal to three times the given distance over which the carriage 15 and pulley 10 moved. Thus closing line 24 is very rapidly supplied to block and tackle 26 so that a counterweight (not shown) on the lower block rapidly moves the lower block downward from the upper block and spreads the jaws of the clamshell bucket 27 to the wide open position.

The carriage frame 20 is made of inter-communicating tubular sides and ends 18, 19, 21 and 22 reinforced at the corners of the frame by triangles 72 and adapted for mounting on the upper girders 73 of a crane boom 29 (Figure l) by means of angles 74. The hollow interior of frame 20 is occupied by air at reduced pressure produced therein by the vacuum action of the engine (not shown) through line 76, check valve 77 and T 78. Air under reduced pressure from inside frame 20 is used to actuate diaphragm valve 46, through control valve 47 and indicated connecting vacuum line 79, as described above. A vacuum release valve 80 is mounted on the inside wall of tubular end 22 for actuation by carriage 15 for safety release of vacuum should the carriage accidentally be permitted to contact the tubular end 22.

Another specific embodiment of the invention is shown in Figure 8. In this embodiment a moveable pulley S1, engaging closing line 24, is rotatably mounted on the end of a piston rod 82 connected to a piston (not shown) inside a hydraulic cylinder 83. The hydraulic cylinder 83 can be mounted on a boom (not shown) and is connected to a hydraulic system comprising a hydraulic oil tank 84, a hydraulic pump 86, a control valve 87, and a connecting conduit line .39. A sheave 91 is rotatably mounted on cylinder 83 as shown, or on the boom (not shown.)

When clamshell bucket 27 is in the open position, and it is desired to close it rapidly and forcefully to load it, drum 43 is rotated to reel in and wind up closing line 24, and hydraulic fluid under pressure is pumped into cylinder- 83' through control valve 87 in conduit line 89 by opening valve 87. This actuates the piston rod 82, forcing it outwardly of cylinder 83, and causes pulley 81 to move toward sheave 28 and relative to closing line 24. Such movement of pulley 81 causes a rapid lengthening of the strand of closing line 24 indicated at 92, approaching pulley 81 from below, and the strand 93 leaving pulley 81 from above. The total amount of lengthening of the two strands, 92 and 93 is about equal to twice the distance of outward movement of pulley 81, and is added to the amount of closing line 24 reeled in and wound up by drum 43, which is continued in rotation. Thus a very rapid and forceful closing of bucket 27 is accomplished.

To rapidly open bucket 27, drum 43 is rotated to unwind closing line 24. At the same time, pulley 81 is withdrawn toward hydraulic cylinder 83. by exhausting hydraulic fluid from cylinder 83 through conduit line 89 with the aid of control valve $7. The rapid inward movement of pulley 81 causes strands 92 and 93 of closing line 24 to shorten a length about equal to the distance pulley 81 .moves inwardly, and adds-this length of line tofthe amount of closing line24 reeled out by drum 43..

It can be seen that this greatly speeds up the opening of bucket 27 and saves a considerable amount of time during both the opening and closing operations.

It will be understood that any convenient and practical means can be used to move pulley in the specific embodiment described in connection with Figures 1 to 7, or to move pulley 81 in the specific embodiment described in connection with Figure 8. Also, it will be understood that instead of moving only one pulley 10 or 81, a plurality of pulleys in a single block, or separated from each other, can be moved simultaneously or at different times to elongate or shorten any number of strands of closing line in the general manner described above.

The foregoing description is primarily for explanatory purposes, and is given to illustrate specific embodiments of the invention. It is understood that many variations in the structure, design and details of the clamshell bucket closure attachment described above will occur to one skilled in the art. Accordingly, it is understood that such changes and modifications in the structure, design and details of the specific embodiments of the invention illustrated and described above may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is:

1. In combination with a closing line block and tackle mounted in a clamshell bucket, the improvement comprising pulley means separate from the clamshell bucket engaging a strand of the closing line, and means for moving the pulley means relative to the closing line for increasing the length of the strand of closing line engaged by the pllley means and shortening the strands of the block and tackle.

2. In combination with a closing line block and tackle mounted in a clamshell bucket, the improvement comprising a moveable pulley separate from the clamshell bucket in engagement with the closing line, and means for moving the pulley relative to the closing line and the block and tackle for lengthening the strands of closing line engaged by the pulley and shortening the strands of the block and tackle for rapid closing of the clamshell bucket.

3. A mechanism for rapid closing of a clamshell bucket provided with a closing line passing through a block and tackle for imparting a mechanical advantage to the jaws of the bucket comprising moveable pulley means separate from the clamshell bucket adapted for engaging strands of the closing line, and means for moving the pulley means relative to the closing line and the block and tackle for lengthening the strands of closing line engaged by the pulley means and shortening the strands of closing line between the pulleys in the block and tackle during closing of the bucket.

4. A mechanism for rapid closing of a clamshell bucket provided with a closing line passing through a block and tackle for imparting a mechanical advantage to the jaws of the bucket comprising moveable pulley means separate from the clamshell bucket adapted for engaging strands of the closing line, and hydraulic piston and cylinder means for moving the pulley means relative to the closing line and the block and tackle for lengthening the strands of closing line engaged by the pulley means and shortening the strands of closing line between the pulleys in the block and tackle during closing of the bucket.

5. A mechanism for rapid closing of a clamshell bucket provided with a closing line passing through a block and tackle for imparting a mechanical advantage to the jaws of the bucket comprising a moveable pulley means separate from the clamshell bucket adapted for engaging strands of the closing line, and moveable carriage means carrying the pulley means and adapted for moving the pulley means relative to the closing line and the block and tackle for lengthening the strands of closing line engaged by the pulley means and shortening the strands of closing line between the pulleys in the block and tackle during closing of the bucket.

6. A mechanism for rapid closing of a clamshell bucket provided with a closing line passing through a block and tackle for imparting a mechanical advantage to the jaws of the bucket comprising a moveable pulley separate from the clamshell bucket operatively engaging the closing line, a sheave operatively engaging the closing line and positioned for reversing the direction of the closing line passing from the pulley to the sheave, and moveable carriage means carrying the pulley and adapted for moving the pulley relative to the closing line and the block and tackle for lengthening strands of closing line engaged by the pulley and the sheave and shortening strands of closing line between the pulleys in the block and tackle during closing of the bucket.

7. A mechanism for rapid closing of a clamshell bucket provided with a closing line passing through a block and tackle for imparting a mechanical advantage to the jaws of the bucket comprising a movable pulley operatively engaging the closing line, a sheave operatively engaging the closing line and positioned for reversing the direction of the closing line passing from the pulley to the sheave, and movable carriage means carrying the pulley and adapted for moving the pulley relative to the closing line for lengthening strands thereof engaged by the pulley and the sheave and shortening strands of closing line between the pulleys in the block and tackle during the closing of the bucket, said movable carriage means comprising platform means for carrying the movable pulley, and frame means for movably mounting the carriage means on the boom of a crane.

8. A mechanism for rapid closing of a clamshell bucket provided with a closing line passing through a block and tackle for imparting a mechanical advantage to the jaws of the bucket comprising a movable pulley operatively engaging the closing line, a sheave operatively engaging the closing line and positioned for reversing the direction of the closing line passing from the pulley to the sheave, and movable carriage means carrying the pulley and adapted for moving the pulley relative to the closing line for lengthening strands thereof engaged by the pulley and the sheave and shortening strands of closing line between the pulleys in the block and tackle during the closing of the bucket, said movable carriage means comprising platform means for carrying the movable pulley, frame means for movably mounting the carriage means on the boom of a crane, roller means mounted on the movable carriage means for rolling contact with rails on the frame means, rack and pinion means associated with the carriage means and the frame means for the operative meshing during movement of the carriage means, and brake means associated with the rack and pinion means for controlling movement of the carriage means.

References Cited in the file of this patent UNITED STATES PATENTS 2,274,168 Scharpenberg Feb. 24, 1942 2,423,916 Walker July 15, 1947 2,588,037 Orton Mar. 4, 1952 2,678,190 Crake May 11, 1954 

